1. Technical Field
This disclosure relates to oxygen scavenging articles. More specifically, the disclosure relates to oxygen scavenging materials containing moisture and systems for and methods of making such articles
2. Description of Related Art
Flexible food packaging materials such as used to form a plastic pouch usually require good oxygen barrier properties in order to prevent microbial growth and preserve the freshness of the food. This need can be exemplified by packages such as those for beef jerky, sausages, and processed meats, among others. A sachet containing an oxygen scavenger is commonly used in these type food pouches to absorb the head space oxygen and to absorb any oxygen permeating through the package wall. Sachets have been used for some time in ready-to-serve food packages, but they have potential disadvantages and limitations. For example, sachets are generally comingled with the food product, and thus may be accidentally ingested. Sachets also are susceptible to accidental piercing or cutting, which can lead to contamination of the food product. And, sachets are not aesthetically pleasing. In addition, sachets are not generally suited for use in packaging liquid products requiring oxygen scavenging.
As one conventional alternative to using sachets, it is known to purge the ambient air from a container and backfill the container with an inert gas, such as nitrogen. However, this process is costly and does not account for migration of oxygen into the package, for example, after sealing the package.
Extruded articles containing oxygen scavengers in the form of film, tape, ribbon or strands are known and may be advantageous in some packaging applications due to their powder-free construction and integral, usually one-piece format. However, such articles are generally not preferable in low-moisture applications, such as in packaging coffee, because there is insufficient ambient moisture to facilitate absorption of oxygen by the iron.
The following are documents identified by the inventor as relating generally to oxygen scavenging:
U.S. Pat. No. 5,896,994, issued Apr. 27, 1999 to WR Grace for “Sealed Articles,” relates to an oxygen scavenging film strip disposed in a tray package containing oxygen sensitive articles.
U.S. Pat. No. 4,769,175, issued Sep. 6, 1988 to Mitsubishi Gas for “Sheet Like Oxygen Scavenging Agent,” describes mixtures of fiber, iron powder, water, and electrolyte formed into a sheet-like product using a paper making process.
U.S. Pat. No. 4,317,742, issued Mar. 2, 1982 to Teijin for an “Oxygen Scavenging Composition, Heat-Generating Composition, And Heat-Generating Structure,” teaches a heat generating composition capable of scavenging oxygen.
In view of the above-described deficiencies in the art, and shortcomings of the just-listed patents, there is a need in the art for an oxygen scavenger made from a film, tape or ribbon that contains a certain amount of moisture. There also is a need in the art for an oxygen scavenger having an adjustable amount of moisture therein, for example, such that the rate of oxygen scavenging in the container or package is controllable.
There also is a need in the art for an oxygen scavenging article that does not occupy large spaces, is functional and is easy to dispense.
There also is a need in the art for an oxygen scavenger suitable for operating at a water activity of 0.4 or lower, for example, as in connection with food products such as powdery coffee and dry infant food powder. Of noted interest, for example, it is desirable to preserve coffee aroma or flavor for single serving ready-to-brew cups that are approximately 30 cc or larger in volume. In a small food package, oxygen may deteriorate aroma or flavor due to oxidation.
There also is a need in the art for a non-leachable oxygen scavenger, which will not change the taste of the articles with which the scavenger is packaged.
There also is a need in the art for a solution to one or more of the aforementioned products that is a sustainable solution using materials of renewable resources and biodegradable in nature.
There also is a need in the art for an improved method of making an oxygen scavenger such as that described above.